Use of implantable pumps for treating chronic pain conditions has become widely accepted practice when more conservative means of relieving pain have failed. Implantable pump technology can be divided into two primary categories, namely constant flow and programmable. Both technologies incorporate an indwelling catheter to establish a fluid path from a pump disposed subcutaneously to a desired anatomical site, including but not limited to, arterial or venous locations, the epidural space and the intrathecal space of the spine. Some of the reported complications with implanted pumps deal with the connection between the pump and the catheter, including leaks, disconnect and reduced flow. Other reported complications involve the catheter itself, which include but are not limited to, kinking, occlusion, disconnect, malposition, migration and reduced flow. Thus, the success of an implanted pump system is dependent in large part on a successful and dependable connection between the pump and the catheter as well as the design of the catheter and the introduction techniques utilized.
Prior art implantable pumps employ relatively tedious and often complicated means for attaching the catheter to the pump, which also may promote problems for the entire pump and catheter system. For example, screw driven clamping connections are both complicated and unreliable as the required clamping action on the outer diameter of an unsupported catheter increases the risk of collapsing the inner lumen of the catheter. Stent based designs that do utilize internal support solve the problem of internal collapse, but require the additional step of attachment involving multiple sutures around the connection area. The suturing process, as well as the sutures themselves, can lead to broken or severed catheters at the suture site where the suture cuts through the catheter or surrounding support members. Also, variability in suture tying and force applied by the user leads to variability in attachment. Thus, a prior art approach to attaching the catheter to the pump has been to utilize a barbed stem connector. The pump is fit with a barbed or flared outer stem for the catheter to be placed therearound. The problem with these designs, which are common in subcutaneous access ports, is a connection that is relatively unsecured and potential damage to the catheter caused by the barbed section. Another related problem is that it is often difficult to ascertain whether a positive connection between the pump and catheter has been established. This can lead to catheter and/or pump damage as undue force is placed on the attachment system in order to get verification of the connection.
In addition to these drawbacks of the prior art systems, one of the primary concerns to overcome in developing a successful and reliable attachment system is that the catheters are generally very small in diameter while the pumps to which they are connected are relatively large. Thus, it is often physically difficult to make the connection between the pump and the catheter.
Accordingly, it is an object of the present invention, in a system involving an implantable pump and catheter, to provide a catheter system for use with implantable pumps and other known catheter-based systems that will maintain the effectiveness and longevity of the connection and system following implantation thereof.
It is also an object of the present invention to provide a connection between the catheter and the pump which eliminates the need for suturing around the catheter, avoids potential collapse of the catheter or other attendant damage thereto.
It is a further object of the present invention to provide a connection system for an implantable pump and catheter that overcomes the difficulty arising from the size difference between the catheter and pump.
It is yet a further object of the present invention to provide a flexible interface between the catheter and pump body to facilitate attachment of the catheter and minimize strains on the connection.
It is still a further object of the present invention to provide a connection system for an implantable pump and catheter, which is very easy and quick to implement.
It is also an object of the present invention to provide a connection system for an implantable pump and catheter that confirms a secure connection.
It is another object of the present invention to provide a connection system for an implantable pump and catheter that is reliable and long-lasting.
It is yet another object of the present invention to provide a catheter with minimal contained dead space at the tip to minimize possible complications from static fluid in the system.
It is still another object of the present invention to provide a stiffening stylet to facilitate positioning of the catheter that is easy to remove and minimizes bunching and displacement of the catheter tip during removal of the stylet.
Further objects and advantages of the present invention will become apparent from the ensuing description and drawings.